In washing machines for domestic use, the detergent is usually manually introduced into a chamber and flushed with water into the suds container after the wash cycle has started. The user must observe the dosage instructions for the particular detergent used, and take care to fill the correct amount of treating agent into a chamber in the dispenser box.
To facilitate charging with liquid or viscous treating agents, such as detergents or fabric softeners, EP 1 731 654 A1 describes a dispensing system in which are inserted cartridges containing a supply of detergent or treating agent therein. The cartridges are respectively inserted into a chamber provided in the detergent dispenser drawer. A piston is pushed into the cartridge, moving the bottom portion of the cartridge inward so as to create a pressure which will press the detergent out of the opening located at the opposite end. Attached to the piston is a plunger which extends through the control panel to the exterior of the washing machine housing, and ends as a control knob. The amount of detergent to be dispensed is determined by the distance traveled by the piston as it is pressed into the cartridge, said distance being a portion of the total plunger distance to be pressed in. Here, the user must ensure that the proper amount of detergent dispensed in each time a dispensing operation is carried out.
To facilitate charging with detergent, automatic dispensing systems can be used in which a relatively large amount of detergent is stored in a supply container. Once a wash cycle is started, the preset amount of detergent will then be added to the wash liquid, which eliminates the need for the user to ensure that the proper amount of detergent is filled in each time a wash cycle is carried out. Such dispensing systems are frequently used especially in industrial washing machines.
German document DE 33 02 893 C2 describes a washing machine having a dispensing system for liquid detergents, which is disposed separately from the washing machine. The dispensing system includes a separate housing in which are fixedly installed two supply containers for additives and which accommodates a control device and the metering pump. Water from the suds container is conveyed through hose connections to the dispensing system, where the additive is added to this water. The water/additive mixture is pumped into the washing machine through a second conduit in region of the flush-in channel for fresh water supply. The dispensing system described therein is designed as a separate add-on unit, for which an additional, predetermined fixed place must be provided laterally adjacent to the washing machine. Connection of the dispensing system to the washing machine is via two hoses or pipes and a cable for power supply to the pump and for signal and/or data transmission. Space constraints make it difficult to access the containers for filling or cleaning.
Another dispensing system for liquid additives is described in DE 10 2005 050 083 A1. In that patent application, a supply container for liquid detergents is located outside the washing machine and connected thereto via a hose line. Disposed within the washing machine is the metering pump, which delivers the liquid or viscous detergent through a hose line to the lower region of the suds container. The metering pump is controlled by the washing machine controller which, based on the ON-time, determines the amount of detergent to be dispensed at any one time.
A dispensing system for liquid additives for use in a dishwasher is described in post-published documents DE 10 2006 043 973 A1 and DE 10 2006 043 919 A1. In those documents, a cartridge containing the treating agent is inserted into a receiving compartment of the dispensing system. The bottom of the cartridge is pierced by cannulas allowing the treating agent to pass from the cartridge to the treatment chamber. A controllable valve is used to dispense the predetermined amount, the amount delivered being determined by the opening time of the valve.